The central United States is not a good air-mass source region because
it is located in the middle latitudes
Why is there no maritime Arctic air mass?
But mA-type
(maritime Arctic) does not exist
. Continental Polar air masses form over large, high- latitude land masses, such as northern Canada or Siberia. cP air masses are cold and extremely dry. Wintertime cooling over these land areas cause the atmosphere to become very stable (even inversion).
Why would a continental polar air mass not be welcome in the central United States in the winter but is very welcome in the summer?
Why is continental polar air mass not welcome to the Central Plains in winter and yet very welcome in summer? They are not welcome in the winter
because they can potentially reach southern states and can ruin a season of crops as it is dry and frigid
.
What is the difference between a continental air mass and a maritime air mass?
Maritime air masses form over water and are humid.
Continental air masses form over land and are dry
.
When a cP air mass passes over warmer waters Great Lakes it produces?
If the temperature difference between the air and water are large, rapid evaporation causes the air to saturate and form a fog. These are
steam fogs
(Chapter 5). Steam fog is common over the Great Lakes and the north Atlantic in fall and winter when the cP air flows over the warm waters (Figure 9.11).
Which air mass is most common over Great Britain?
Polar maritime
is the most common air mass to affect the British Isles. This air mass starts very cold and dry but during its long passage over the relatively warm waters of the North Atlantic its temperature rises rapidly and it becomes unstable to a great depth.
Which air mass is the coldest?
The coldest air masses are
Arctic air masses
. These air masses originate at the poles of the Earth in Greenland and Antarctica.
What is a good air mass source region?
Parts of the Earth’s surface where the air can stagnate and gradually gain properties of the underlying surface are called source regions. The main source regions are the
high pressure belts in the subtropics
(giving rise to tropical air masses) and around the poles (the source for polar air masses).
What is the best source region for an air mass?
The best source regions for air masses are
large flat areas where air can be stagnant long enough to take on the characteristics of the surface below
.
Where do air masses typically clash?
Polar and tropical air masses typically clash in
the middle latitudes
, producing some very changeable climates. The surface where the air masses meet is termed a ‘front’.
What are the 5 types of air mass?
These are Polar (cold), Arctic (very cold), Equatorial (warm and very moist), and Tropical (warm). In the United States the major air mass types are typically
continental Polar, maritime Polar, continental Tropical, and maritime Tropical
.
What are the 2 major causes for moving air masses in North America?
One major influence of air mass movement is
the upper level winds such as the upper level winds associated with the jet stream
. The jet stream wind is often referred to as a steering wind. The troughs and ridges of the jet stream will help transport cold air toward lower latitudes and warm air toward high latitudes.
What type of weather does an air mass usually bring?
Continental air masses are usually relatively dry and usually bring
fair weather
. Maritime air masses are usually humid and may bring precipitation.
Which two air masses have the greatest impact on the Pacific coast of North America?
Which two air masses have the greatest impact on the Pacific coast of North America?
Maritime polar air masses
, abbreviated mP on weather maps, tend to dominate the Pacific coast region.
What type of air masses generally affect the United States?
Five air masses affect the United States during the course of a typical year:
continental polar, continental arctic, continental tropical, maritime polar, and maritime tropical
. Continental air masses are characterized by dry air near the surface while maritime air masses are moist.
What happens when two air masses meet?
When two different air masses come into contact,
they don’t mix
. They push against each other along a line called a front. When a warm air mass meets a cold air mass, the warm air rises since it is lighter. At high altitude it cools, and the water vapor it contains condenses.
